The invention relates to roller compactors for compacting roadways or other earthen structures. In particular the invention relates to a side-mounted vibratory roller for rolling sloped shoulder areas.
The construction of roadways and related features typically requires the use of machinery to compact or densify the roadway material. The roadway material can be any base that needs to be compacted to finished state, e.g. asphalt, aggregate, stone, earth, gravel, and the like. A variety of machines in recent decades have been created to satisfy these compacting needs and many machines have become specialized for specific compacting applications. One general class of machinery for compacting is known as xe2x80x9croad rollersxe2x80x9d. Road rollers contain one or more cylindrical drums that roll over the material being compacted. Typically these road rollers comprise (in a broad sense) a frame, front and rear drums, an engine, and a driving/steering mechanism for a driver. The rolling action is often enhanced by a vibration action. The vibration action can be caused by a vibration unit inside the drum or external to it. The most common approach for producing vibration in a road roller is the use of unbalanced weights that are mounted on a rotating shaft inside the drum.
One particular use of such vibratory road rollers has been to roll the xe2x80x9cshoulderxe2x80x9d area of roadways and other surfaces such as parking lots and recreation areas. The shoulder area is a strip (usually a few feet or less) of material just off the edge of the main surface that is often filled and compacted for safety and structural (e.g. drainage) reasons. In the case of a roadway shoulder, when a vehicle veers off of the road, the shoulder area provides a smooth and safer transition off of the roadway.
Shoulders are made by filling the area with aggregate or asphalt at a sloped angle and then compacting with a vibratory roller of some type. The shoulder area is compacted to avoid having a loose, unsafe gravel area on the shoulder and to make the shoulder area maintain its stability longer. Additionally, at the time of compacting the shoulder, the seam where the main surface area and shoulder meet is also xe2x80x9cpinchedxe2x80x9d. Pinching involves compacting the seam where the main surface and the shoulder meet to help ensure a smooth transition from the main surface to the shoulder. In practice, the operator of a road roller will perform the pinching and the shoulder compacting in two separate rolls. For example, the operator will drive forward to pinch the seam and then will drive in reverse to compact the shoulder wedge only. Additionally, a third pass may be performed as the operator drives forward over the pinched or shoulder wedge again. This leads to an inefficiency in the process as two or more passes are performed. This procedure also creates an additional hazard because part of the operation is done with the operator traveling in reverse which is more difficult than traveling forward.
Roadways are often elevated somewhat from the surrounding environment for safety and drainage reasons. This design creates shoulder areas that are sloped down from the roadway. It is common for this slope to be up to 10 degrees or more. In fact, there is an incentive to make this slope steeper because less material (e.g. aggregate) is generally required to make a steeper shoulder thus leading to cost savings. This creates a hazard for the construction crew in compacting such sloped shoulders. In a shoulder rolling operation, typically the operator of the road roller will travel forwards and backwards generally parallel to the roadway on the seam and shoulder area. During this compaction the road roller is being operated in a tilted manner at the same angle as the slope in the shoulder. It has been recognized that in some circumstances operating a roller in such a tilted manner may increase the chance of the roller tipping and potentially causing harm to the operator. It would be safer if the operator of shoulder compacting machinery were not on the compactor itself. While compactors are available in which the operator does not ride on the roller itself, but rather pushes or guides it, they are not very practical for shoulder rolling (especially larger projects) because of the slower speeds and difficulty of controlling them on sloped surfaces. Additionally, the walk behind type compacters tend to roll or slide down out of control down the grade which can cause operator injury and/or equipment damage. Because of these disadvantages, all or nearly all roadway shoulder compacting operations (to the inventors"" knowledge) are performed with a road roller having an operator seated on the roller itself.
A large variety of solutions have been created for rolling and compacting operations in general, as can be seen from a cursory review of published patent documents. Some specific, non-exhaustive, examples of United States Patents that disclose rolling compactor machines include: U.S. Pat. No. 3,302,540 (xe2x80x9cFuentesxe2x80x9d), U.S. Pat. No. 3,947,142 (xe2x80x9cTakata et al.xe2x80x9d), U.S. Pat. No. 4,471,850 (xe2x80x9cRotzxe2x80x9d), U.S. Pat. No. 4,662,779 and U.S. Pat. No. 3,403,610 (xe2x80x9cKalteneggerxe2x80x9d), U.S. Pat. No. 4,699,543 (xe2x80x9cMio et al.xe2x80x9d), U.S. Pat. No. 4,861,189 (xe2x80x9cFukukawa et al.xe2x80x9d), U.S. Pat. No. 4,878,544 (xe2x80x9cBarnhartxe2x80x9d), U.S. Pat. No. 4,964,753 (xe2x80x9cCiminelli et al.xe2x80x9d), U.S. Pat. No. 5,046,891 (xe2x80x9cVuralxe2x80x9d), U.S. Pat. No. 5,082,396 (xe2x80x9cPolacekxe2x80x9d). All of these patents are hereby incorporated by reference.
Rotz teaches a drum-type asphalt compactor having a pair of drum-compactor units. An important feature of Rotz""s invention is the articulated nature of the two drums. As with the present invention, the two drums are joined together with a joint means and the two sections do not share a common frame. Polacek also discloses this type of roller. Polacek""s invention is a vibratory roller having a frame comprised of pivotally interconnected front and rear subframes.
Kaltenegger discloses a road roller that includes a pair of rotatable roller drums each having axially opposite end portions. A key feature of the Kaltenegger machine is the ability of the two drums to pivot relative to one another. Similar to Kaltenegger, the Takata et al. patent teaches a tandem drum-type pavement compacting machine having front and rear drums with the ability of pivoting or being xe2x80x9coffsetxe2x80x9d. However, unlike Kaltenegger, Takata et al. further discloses the ability of finishing surfaces not lying in a flat plane because the front drum can oscillate or pivot relative to the chassis and the rear drum.
A different approach to compacting is taken by Barnhart. The Barnhart patent discloses a compactor that is not self-propelled and is designed as an attachment to an earth moving equipment. While Barnhart is similar to the present invention in using an attachment, Barnhart""s invention is rear mounted and still suffers from the limitation of requiring a driver to drive on the shoulder area in order to compact it.
A number of other patents have specifically addressed the difficulty of working in sloped or inclined environments. Fukukawa et al. discloses a method for paving inclined and/or curved surfaces using a vehicle which is connected by wires to an anchor vehicle. Mio et al. also discloses a paving machine which uses a boom extending from a truck. Lastly, Fuentes teaches a method and apparatus for compacting, rolling, and finishing the earth especially on sloped surfaces. Fuentes"" apparatus comprises a truck with a compacting apparatus with a single rolling drum. While these inventions all address the problem of working in a sloped environment their solutions are not completely satisfactory. In particular, they would not be efficiently usable for rolling the shoulder area of a roadway in a single pass while the vehicle drives on the roadway. Additionally, these designs are probably too heavy to operate on a newly paved roadway as they would destroy the surface. Thus, for practicality and cost effectiveness, these options are not workable solutions for compacting shoulder areas.
Despite the many existing designs, there continues to be a need for improved designs for roadway compacting machinery, especially for compacting on sloped surfaces such as a roadway shoulder. In particular, there is a need to address the safety of compacting the shoulder areas of roadways by not having an operator drive a compacter in a tilted manner or in a backward direction. Both of these can be tipping hazards. The present invention addresses these needs. Accordingly, the following are stated objections of the present invention.
It is an object of the present invention to reduce or eliminate the tipping dangers associated with rolling roadway shoulders with a driver operated road roller.
It is another object of the invention to provide a compaction roller that can roll a sloped surface (e.g. a road shoulder) while the operator remains safe on a relatively level surface (e.g. the road).
It is an object of the present invention to provide a compaction roller attachment that can be side-mounted to a self driven piece of machinery.
It is an additional object of the present invention to provide a compaction roller capable of pinching the edge of the road and simultaneously rolling the shoulder area in one forward operation.
It is also an object of the invention to provide a compaction roller having two roller drums that can simultaneously compact two surfaces each lying on a different plane.
With these objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims.
The invention is a compaction roller particularly useful for vibration compaction of the shoulder area of roadways and other surfaces requiring reqiiifed compacting. The compactor is designed as an attachment for side-mounting to self-propelled or motorized machinery (e.g. a skid steer front loader). The compaction roller contains: (a) a rear section comprising a frame connected to a rear cylindrical roller, (b) a front section comprising a frame connected to a front cylindrical roller; (c) a joining means pivotally connecting said rear and front sections; and (d) a means for attaching to self-propelled machinery in a side mounted fashion.